Sen. Jon Tester is launching an ad today criticizing his Republican challenger, a change from the mostly positive ads the campaign has aired to date.

The Democrat's ad targets Rep. Denny Rehberg's House-floor voting record, charging that he supported a 2011 appropriations bill that reduced funding for breast cancer screenings. It features Lisa Jones, a cancer survivor, discussing how the cuts could have affected her recovery.

"It's been nearly a year since they found the cancer, so it's very personal for me that Congressman Dennis Rehberg voted to eliminate funding for breast cancer screenings, even from the clinic that saved my life, while protecting tax breaks for multimillionaires," Jones says in the ad. "Talk about wrong priorities."

The campaign spent $60,000 to run the ad on broadcast and cable, according to a source with knowledge of the buy.